Recently, various types of display devices of what is called memory-in-pixel (MIP) system, comprising a memory module capable of storing data in pixels, have been proposed. As a gradation expression system of such a display device, an area gradation (gray scale or tone) method of dividing one pixel into regions (segments) and implementing gradation display by combination of area of these regions is well known.
In the area gradation method, a pixel electrode of a corresponding shape is disposed in each of the divided regions. Area of the pixel electrode (area of a segment) has magnitude responding to the gradation which should express in the segment. However, the shape and arrangement of the segments may be complicated if the number of segments is increased in each unit pixel to implement multi-gradation.